Thursday, October 28, 2010

Wildfire Fuels Debate Over Land-Burning in Africa

"Fire is normally considered as the number one enemy of conservationists, so some here would be surprised to find out that a number of Malagasy species are adapted to fire and indeed would probably decline in the absence of this condition," Birkinshaw said.

Although the finding on mature plants is encouraging, Birkinshaw said younger vegetation may be more seriously impacted by fire. Woody rootstocks and thick bark protect mature plants, adaptations that seedlings are too young to have.

This October, Birkinshaw and his colleagues plan to burn small plots on Ibity to more closely study the impact on younger plants.

"I think one wouldn't want to give the impression that fire is good for Madagascar's biodiversityit isn't, especially at its current frequency. But without wishing to leap to conclusions at the start of the study, we will likely find some species for which the ideal environmental conditions would include an occasional burn," he said.

Christian Kullan environmental scientist at Monash University in Melbourne, Australia, and author of the book Isle of Fire: The Political Ecology of Landscape Burning in Madagascaris not surprised by the preliminary findings.

"Since fire has always played a role in Malagasy environments, some species are favored by the presence of fire," he said. Prior to the seasonal burning of fields by farmers and ranchers, intense lightning-caused fires swept across the island, he added.

Burning Balance

When humans arrived on Madagascar about 1,500 years ago, they used fire to sculpt the landscape to their needs, according to Kull. The biggest changes were in the highlands, where a mix of woodlands, savanna, and open areas became dominated by grasslands.

When the French colonized Madagascar in 1896, administrators, conservationists, and scientists sought to control the rates of burning to stem the loss of forests and prevent soil erosion.

Laws intended to punish burning were carried over when Madagascar won independence in 1960 and are still enforced today.

However, Kull said anecdotal evidence and government data suggest that rates of burning have remained consistent for the past century. This burn rate serves Malagasy needs to renew pasture, fight brush encroachment, and prevent the buildup of fuels, he said

"The main difference is that with a hundred years of government antifire activity, people now burn out of sight, at night, when nobody is looking," he said.

Birkinshaw said that a group of about 200 local villagers, including women and children, banded together to beat out the Ibity fire last October out of social responsibility and fear of being blamed "for not doing anything."

Given the steady rates of burning over the past hundred years, conservationists are concerned it is eroding the island's biodiversity.

"The ideal frequency of burning is unknown and would depend on the desired abundance of fire-tolerant versus fire-intolerant speciessomething that is probably subjective. But presumably one would want to approach the natural state," Birkinshaw said.

According to Kull, determining the ideal rate of burning is a complex process. Madagascan farmers "use fire to shape biodiversity to their needs. From a botanical perspective, this probably means less species. But from a human perspective, this is what we do," he said.